Joe Flacco threw 10 interception on 531 pass attempts last regular season. In the Ravens' three preseason games, on 489 fewer passes, Flacco already has turned the ball over four times.

Some of this falls under the ol' "Don't read too much into preseason results" banner. But with Flacco trying to settle in to an offense without Anquan Boldin and injured tight end Dennis Pitta, there might be cause for a tad bit more alarm.

"I think it is that, because Joe is not one to throw interceptions, as we all know," Ravens coach John Harbaugh said Thursday, when asked if Flacco needed to get some interceptions out of his system during the preseason. "We’ll be concerned about them -- Joe more than anybody.

"A lot of that is [that] he’s trying to get a feel for guys. I can’t say if everybody was exactly where they were supposed to be on the routes or not -- that’s the stuff we’ll look at."

It won't take Harbaugh and his staff to determine that at least one piece was out of place on Flacco's first INT in a 34-27 loss to Carolina, which Drayton Florence took back for six. With the Panthers showing blitz, Flacco tried to hit third-year receiver Tandon Doss on a hot route. Doss, though, failed to make an adjustment, resulting in a costly miscommunication.

Here's a look at how both teams lined up. Doss and Carolina CB Captain Munnerlyn are highlighted, and the Panthers also had two deep safeties who are not pictured here:

Carolina had five defenders, including linebackers Luke Kuechly and Thomas Davis at the line -- Kuechly and Davis lined up next to each other, over center Gino Gradkowski. Munnerlyn also inched closer toward the hash mark before the snap, with his eyes planted firmly on Flacco in the backfield.

Flacco did make a quick, rather indistinguishable hand gesture prior to calling for the snap, perhaps signaling an adjustment to the coming pressure. More likely, though, the determination on a hot read for this play either was determined in the huddle or is a built-in cue a receiver must pick up on when his defender blitzes.

A "hot read" essentially scraps a receiver's called route on a play in favor of a short, quick pass to counter a blitz. Because Munnerlyn blitzed on this snap, Doss should have adjusted in such fashion.

Why do offenses do this? Well, as you can see in the shot below, with Munnerlyn leaving Doss to blitz off Flacco's blindside, a huge opening presents itself in the Carolina defense.

Davis dropped out of his blitz to cover the middle of the field and another defender (it looks to be end Charles Johnson, though limited replay options make it tough to tell for sure) also fell back in coverage. The defensive play call allowed the Panthers to pressure Flacco, both with Kuechly up the middle and Munnerlyn to his left, while still keeping the majority of the field under wraps.

There were two gaps. One was in the flat to either direction of Flacco, but RB Ray Rice could not release out to that area, because he stayed in to help pick up Kuechly's blitz.

The other was right where Flacco turned his eyes at the snap, in Doss's direction, a couple of yards from the line.

Safety Mike Mitchell recognized what Flacco wanted here, reading the QB's eyes and jumping the route. He whiffed on trying to swat the pass, thus allowing the ball to travel right into Florence's hands.

The play looked bad for Flacco, both in real time and on the stat sheet -- and, in reality, even if Doss had turned, Flacco might have sailed the pass over his head. This is a confidence throw for a quarterback, one where he expects his receiver to analyze the defense in front of him, adjust and get open.

Doss failed to do that, instead sticking with his called route, which appeared to be some sort of out-and-up move. The result of Doss's failure to switch his plan when Munnerlyn blitzed was a huge play for the Carolina defense.

The good news for Baltimore is that this was a mistake that's easily correctable moving forward. However, for it to work in the future, Flacco will have to trust his receiver -- be it Doss or someone else -- to be there. A few more errors like this one from Thursday, and it may be harder for Flacco to do that.